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Small bowel (small intestine)

Infectious disorders

Bacterial enterocolitis

Reviewer: Hanni Gulwani, M.D. (see Reviewers page)
Revised: 16 December 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.


● Bacterial related disease due to either ingestion of pre-formed toxin (Staphylococcus aureus, Vibrio cholera, Clostridium perfringens), infection by toxigenic organisms or infection by enteroinvasive organisms which invade and destroy mucosal epithelium cells (eMedicine)
● Bacterial adhere to mucosal epithelial cells, elaborate enterotoxins, have capacity to invade
● Adhere by plasmid-mediated adhesins (E. coli, V. cholera), fimbriae or pili
● Adhesion destroys microvilli brush border

Clinical features

● Complications due to massive fluid loss and loss of mucosal barrier include dehydration, sepsis, perforation
Salmonella: invades via transcytosis with minimal epithelial damage
Yersinia enterocolitica: penetrates ileal mucosa, multiplies in Peyer’s patches and regional lymph nodes
Insidious infection: Yersinia and Mycobacterium tuberculosis
Cytotoxins: Shiga toxin, enterohemorrhagic E. coli

● Bind to cell membrane, enter cell, activates massive electrolyte secretion (cholera toxin, E. coli heat-labile and heat-stable toxins produce travelers diarrhea)
● No white blood cells in stool

Bacterial invasion:
● Enteroinvasive E coli and Shigella have plasmid that mediates epithelial cell invasion via microbe-simulated endocytosis; then intracellular proliferation, cell lysis, cell to cell spread

Patients ingest preformed toxins:
● Symptoms within hours
● Explosive diarrhea and acute abdominal distress
● 1-2 days
C. botulinum may produce rapid, fatal respiratory failure

Infection with enteric pathogens:
● Incubation of hours-days
● Diarrhea and dehydration (secretory enterotoxin) or dysentery (cytotoxin or enteroinvasive)

Travelers diarrhea:
● Fecally contaminated water/food
● Begins abruptly, subsides in 2-3 days

Micro description

● Decreased epithelial cell maturation, increased mitotic figures, hyperemia and edema of lamina propria, variable neutrophils, modest villus blunting of small bowel
Late - lymphocytes, plasma cells, regenerative change

Differential diagnosis

Inflammatory bowel disease

End of Small bowel (small intestine) > Infectious disorders > Bacterial enterocolitis

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